Distributed process control systems, like those used in chemical, petroleum or other processes, typically include one or more process controllers and input/output (I/O) devices communicatively coupled to at least one host or operator workstation and to one or more field devices via analog, digital or combined analog/digital buses, or via a wireless communication link or network. The field devices, which may be, for example, valves, valve positioners, switches, and transmitters (e.g., temperature, pressure, level and flow rate sensors), are located within the process environment and generally perform physical or process control functions, such as opening or closing valves, or measuring process parameters to control one or more processes executing within the process plant or system. Smart field devices, such as field devices conforming to the well-known Fieldbus protocol may also perform control calculations, alarming functions, and other control functions commonly implemented within a controller. The process controllers, which are also typically located within the plant environment, receive signals indicative of process measurements made by sensors or field devices and/or other information pertaining to the field devices and execute a controller application that runs, for example, different control modules that make process control decisions, generate control signals based on the received information, and coordinate with the control modules or blocks being performed in the field devices, such as HART®, Wireless HART®, and FOUNDATION® Fieldbus field devices. The control modules in the controller send the control signals over the communication lines or links to the field devices to thereby control the operation of at least a portion of the process plant or system.
Information from the field devices and the controller is usually made available over a data highway to one or more other hardware devices, such as operator workstations, personal computers, or computing devices, data historians, report generators, centralized databases, or other centralized administrative computing devices that are typically, but not always, placed in control rooms or other locations away from the harsher plant environment. Each of these hardware devices typically, though not always, is centralized across the process plant or across a portion of the process plant. These hardware devices run applications that may, for example, enable an operator to perform functions with respect to controlling a process and/or operating the process plant, such as changing settings of the process control routine, modifying the operation of the control modules within the controllers or the field devices, viewing the current state of the process, viewing alarms generated by field devices and controllers, simulating the operation of the process for the purpose of training personnel or testing the process control software, keeping and updating a configuration database, etc. The data highway utilized by the hardware devices, controllers, and field devices may include a wired communication path, a wireless communication path, or a combination of wired and wireless communication paths.
As an example, the DeltaV™ control system, sold by Emerson Process Management, includes multiple applications stored within and executed by different devices located at diverse places within a process plant. A configuration application, which resides in one or more operator workstations or computing devices, enables users to create or change process control modules and download these process control modules via a data highway to dedicated distributed controllers. Typically, these control modules are made up of communicatively interconnected function blocks, which perform functions within the control scheme based on inputs thereto and which provide outputs to other function blocks within the control scheme. The configuration application may also allow a configuration designer to create or change operator interfaces which are used by a viewing application to display data to an operator and to enable the operator to change settings, such as set points, within the process control routines. Each dedicated controller and, in some cases, one or more field devices, stores and executes a respective controller application that runs the control modules assigned and downloaded thereto to implement actual process control functionality. The viewing applications, which may be executed on one or more operator workstations (or on one or more remote computing devices in communicative connection with the operator workstations and the data highway), receive data from the controller application via the data highway and display this data to process control system designers, operators, or users using the operator interfaces, and may provide any of a number of different views, such as an operator's view, an engineer's view, a technician's view, etc. A data historian application is typically stored in and executed by a data historian device that collects and stores some or all of the data provided across the data highway while a configuration database application may run in a still further computer attached to the data highway to store the current process control routine configuration and data associated therewith. Alternatively, the configuration database may be located in the same workstation as the configuration application.
As noted above, operator display applications are typically implemented on a system wide basis in one or more of the workstations and provide displays to the operator or maintenance persons regarding the operating state of the control system or the devices within the plant. Typically, these displays take the form of alarming displays that receive alarms generated by controllers or devices within the process plant, control displays indicating the operating state of the controllers and other devices within the process plant, maintenance displays indicating the operating state of the devices within the process plant, etc. These displays are generally configured to display, in known manners, information or data received from the process control modules or the devices within the process plant. In some known systems, displays have a graphic associated with a physical or logical element that is communicatively tied to the physical or logical element to receive data about the physical or logical element. The graphic may be changed on the display screen based on the received data to illustrate, for example, that a tank is half full, to illustrate the flow measured by a flow sensor, etc.
In some known systems, operators use I/O devices such as a keyboard and a mouse to control the process control modules or the devices within the process plant. For example, an operator may click on a graphic representation of a tank and as a result, the operator display application displays a faceplate for allowing the operator to set the level in the tank using a slider bar, for example. Traditionally, operators interacted with physical control panels which involved flipping switches, turning knobs, etc., to control the process or the devices within the process plant. While I/O devices such as a keyboard and mouse can be used to control the process, such devices allow for only one target (e.g., a single tank) to be adjusted at a time. Moreover, I/O devices can be cumbersome increasing the size and weight of a personal computing device and making it difficult for personal computing devices to be portable. Furthermore, controlling process control modules and devices within the process plant using faceplates may be counterintuitive compared to traditional methods of interacting with physical control panels by flipping switches, turning knobs, etc., and receiving haptic feedback when the adjustment may lead to a dangerous condition in the process plant.